District of Columbia Hazmat CDL Practice Test

This is a free 20-question practice test for the Hazmat portion of the District of Columbia Commercial Driver's License knowledge exam. Questions are pulled from a pool of 68 drawn from the AAMVA CDL Manual, which is the source document the District of Columbia Department of Motor Vehicles uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in District of Columbia.

Question 1 of 20

Hazardous materials are products that:

Are heavier than normal cargo
Pose a risk to health, safety, or property during transportation
Can only be hauled at night
Require a special trailer color

Correct. Hazardous materials (hazmat) are products that pose a risk to health, safety, or property during transportation. Hazmat regulations are codified in 49 CFR.

Question 2 of 20

The Hazardous Materials Table (HMT) lists:

Only flammable liquids
Each hazardous material with its proper shipping name, hazard class, ID number, packing group, and required label
Only items shipped by air
Only items shipped by truck

Correct. The HMT in 49 CFR §172.101 lists every hazardous material with its proper shipping name, hazard class, identification number, packing group, label requirements, and special provisions.

Question 3 of 20

Placards must be at least how many inches on each side?

10.75 inches (273 mm)
5 inches
15 inches
20 inches

Correct. Placards are diamond-shaped, at least 250 mm (about 10.75 inches) on each side.

Question 4 of 20

The Hazmat (H) endorsement requires:

Only a knowledge test
A knowledge test plus a TSA Threat Assessment background check
Just a fee
A skills test only

Correct. Hazmat applicants pass a knowledge test and complete the TSA Threat Assessment (HME), which involves fingerprints and an FBI background check.

Question 5 of 20

After a hazmat incident, the driver should:

Notify the carrier and complete required reports
Drive home
Wait until the next trip to report
Throw away the shipping paper

Correct. Notify the carrier immediately. Federal incident reports may be required to PHMSA, depending on severity. Retain the shipping paper.

Question 6 of 20

A driver of a hazmat-loaded vehicle must check the tires:

Once before the trip
At the start of the trip and every time the vehicle is parked
Only at fueling
Never

Correct. Hazmat drivers must check tires at the beginning and again each time the vehicle is parked. A flat or smoking tire must be addressed before continuing.

Question 7 of 20

The shipping paper for hazmat must include:

Only the destination
Proper shipping name, hazard class, ID number with UN/NA prefix, packing group, total quantity, and emergency contact
Only the weight
Only the carrier name

Correct. A complete shipping paper includes proper shipping name, hazard class or division, UN/NA ID number, packing group (where applicable), total quantity and unit, and a 24-hour emergency contact.

Question 8 of 20

Hazmat marking on a non-bulk package includes:

Proper shipping name and UN/NA number
Just the weight
Just the destination
Color only

Correct. Non-bulk markings include the proper shipping name and UN/NA identification number, plus consignor/consignee information.

Question 9 of 20

Drivers of hazmat vehicles must avoid which of the following routes when alternatives exist?

Tunnels, narrow streets, and densely populated areas
Interstates
Highways
Rural routes

Correct. Avoid populated areas, narrow streets, tunnels, and other places where an incident would maximize risk. Follow state-designated hazmat routes.

Question 10 of 20

Carrying a hazmat shipment without the required shipping paper:

Is allowed if you remember the cargo
Is a violation; the shipping paper must be present and accessible
Is allowed if you have a phone
Has no consequence

Correct. Operating without proper shipping papers is a regulatory violation and dangerous — emergency responders rely on the paper to identify materials.

Question 11 of 20

Hazmat drivers must report any change of:

Address to the licensing agency
Daily route
Diet
Vehicle paint color

Correct. Address changes must be reported to the state licensing agency in line with state CDL requirements; some states require reporting within 30 days.

Question 12 of 20

Who is responsible for proper hazmat packaging and labeling?

The shipper
The driver
The carrier
The consignee

Correct. The shipper packages, labels, and certifies the materials. The carrier and driver verify and refuse non-compliant shipments.

Question 13 of 20

When you place placards on a vehicle, the placard ID number (when applicable) must:

Be displayed on each side and end of bulk packagings or on placards or orange panels
Not be shown
Be in red ink only
Be a phone number

Correct. Bulk packagings and certain shipments require the four-digit UN/NA number on each side and end of the package, on the placard, or on an orange panel.

Question 14 of 20

A driver may not carry hazmat aboard a vehicle without:

A current Hazmat (H) endorsement on the CDL
A green light
Two cell phones
A reflective vest

Correct. Hauling placardable hazmat requires the H endorsement, which includes a TSA Threat Assessment background check.

Question 15 of 20

When refueling a hazmat-loaded vehicle:

Leave the engine running
Turn off the engine, do not smoke, and someone must control the fueling process
Smoke if you are far enough away
It does not matter

Correct. Engine off, no smoking within 25 feet of the vehicle being fueled, and someone must be in control of the fueling at the nozzle.

Question 16 of 20

You may use a flame to check for hazmat leaks:

When you have a respirator
Never — never use any flame near hazmat
Only at night
Only with permission

Correct. Never use a flame to check anything near hazmat. Use a flashlight or other intrinsically safe light.

Question 17 of 20

The 24-hour emergency response phone number on the shipping paper:

Is optional
Must be provided by the shipper and monitored 24 hours per day
Is the driver's personal phone
Is for billing

Correct. The 24-hour emergency contact must be a person knowledgeable about the materials, available 24/7. Many shippers contract CHEMTREC or similar.

Question 18 of 20

The shipper must certify on the shipping paper that:

The shipment complies with HMR (Hazardous Materials Regulations)
The shipment is heavy
The driver is qualified
The truck is empty

Correct. The shipper signs a certification that the shipment is properly described, packaged, marked, labeled, and complies with HMR.

Question 19 of 20

When parking a placarded hazmat vehicle at a truck stop overnight, you should:

Park in a designated hazmat parking area, follow attendance rules for explosives, never block traffic
Park behind the fuel pumps
Park in the entrance
Park anywhere

Correct. Use designated hazmat parking. Explosives and certain other materials require attended parking; review the carrier's policy and federal rules.

Question 20 of 20

You discover a leak in a Class 3 (flammable liquid) shipment. You should:

Continue driving until you find a safe place
Stop, secure the area, notify emergency services, do not transfer cargo on the road, do not move the vehicle further than necessary
Drive faster to deliver the load
Open the placards

Correct. Stop in a safe location, secure the area, call 911, and notify your dispatcher. Do not transfer cargo by the side of the road.

About the District of Columbia Hazmat exam

Most states administer 30 Hazmat questions and require 80% to pass. The exam covers hazard classes, the shipping paper, placards and labels, loading and unloading, driving and parking rules, emergency response, and the Emergency Response Guidebook (ERG).

The District of Columbia Department of Motor Vehicles follows the federal CDL standards established by FMCSA. To earn the Hazmat credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full Hazmat question bank or browse all District of Columbia CDL practice tests.